The trooper was stopped to help a disabled car and another car was slowing to go around when it was struck by the hit-and-run driver and forced into the trooper's car. She had minor injuries.
The patrol is looking for the driver who fled.
It was the second crash this week in which state patrol cars were hit. On Monday night two patrol cars stopped on Interstate 5 in Seattle were damaged in a rear-end collision caused by a man suspected of drunken driving.